1. Field
Example embodiments of the present invention relate generally to wireless systems, carrier reselection (or idle handoff) and traffic redirection in wireless systems having multiple carriers with overlapping coverage areas including wireless systems having carriers representing more than one radio access technology (RAT). Those RATs are specified by various radio access technology standards such as CDMA2000 High Rate Packet Data (HRPD) or Data Optimized (DO), CDMA2000 3G1x, Long Term Evolution (LTE), Universal Mobile Telecommunication System (UMTS), etc.
2. Description of Related Art
When an access terminal (AT) is in idle state and moves across a geographic area having overlapping coverage areas of carriers following different radio access technologies (RATs), inter-RAT idle handoff, or cell re-selection, will be conducted. Conventional methods provide for a hard switch over of hand-off, with the AT changing connection from carriers following a first RAT to carriers following a second RAT. According to conventional methods, 100% of the ATs entering an area with overlapping coverage may be re-directed from the first RAT to the second RAT. Simply performing a hard switch over or hand-off may be more suitable for a case where carriers of two different RATs have coverage areas that only substantially overlap at a border of the coverage areas. In practice, there are many cases where coverage areas of carriers following a first RAT are spotty and are overlapped by a nationwide coverage area of carriers following a second RAT. For example, many operators have networks with High Rate Packet Data (HRPD) RAT, which have nationwide coverage areas, and networks with Long Term Evolution (LTE) RAT, which have spotty coverage areas that overlap the nationwide coverage areas of the HRPD networks.